class Person {
    private String name;
    private int age;
    public void setName(String name) {
    	this.name=name;
    }
    public void setAge(int age) {
    	this.age=age;
    }
    public String getName(){
    	return name;
    }
    public int getAge(){
    	return age;
    }

	public void intro()
	{
		System.out.println("I'm a person of "+age+" old");
	}
}

class Student extends Person {
    private String school;
    public String getSchool() {
    	return school;
    }
    public void setSchool(String school) {
    	this.school =school;
    }

	public void intro()
	{
		System.out.println("I'm a student of "+school);
	}
}

public class TryPerson {
    public static void main(String arg[]){
        Student student = new Student();
        student.setName("DYH");
        student.setAge(100);
        student.setSchool("QDU");

		System.out.println(student.getName());
        System.out.println(student.getAge());
        System.out.println(student.getSchool());
		student.intro();

		/*Person person = new Person();
		person.setName("none");
		person.setAge(1000);
		person.intro(); 
		 evolution*/
    }
}
